September 07, 2005

Jordanian Y chromosomes

New paper on Y chromosomes in Jordan, showing how the smoothness of macro-scale genetic variation often finds significant deviations at the more micro-scale level. It is imperative that such studies be conducted in more Near Eastern populations so that we can understand better the origin and evolution of Caucasoids in the region.

The Y-haplogroup frequency table is also interesting because it lists frequency of haplogroups in several populations. Greek frequency data are compiled from the literature and appear in the final column, and allow us to quantify the non-Caucasoid admixture in Greeks (0.2% Sub-Saharan haplogroup A and 1.3% Asian haplogroup C; total 1.5%). Haplogroup B (0.2%) reported in Greeks in the table is an error (see update below).

Update:

I contacted the authors of the study, pointing out that haplogroup B did not occur in the studies used to obtain results for the Greek population, and they have confirmed that this is the case:

Thank you for your careful revision of our article about Y chromosome in Jordan. Yes, you are right. There is a mistake in table 1. The greek B haplotypes are in fact indeterminated Y*.We apologize for this error.Sincerely yours,

Isolates in a corridor of migrations: a high-resolution analysis of Y-chromosome variation in Jordan

Carlos Flores et al.

Abstract A high-resolution, Y-chromosome analysis using 46 binary markers has been carried out in two Jordan populations, one from the metropolitan area of Amman and the other from the Dead Sea, an area geographically isolated. Comparisons with neighboring populations showed that whereas the sample from Amman did not significantly differ from their Levantine neighbors, the Dead Sea sample clearly behaved as a genetic outlier in the region. Its high R1*-M173 frequency (40%) has until now only been found in northern Cameroonian samples. This contrasts with the comparatively low presence of J representatives (9%), which is the modal clade in Middle Eastern populations, including Amman. The Dead Sea sample also showed a high presence of E3b3a-M34 lineages (31%), which is only comparable to that found in Ethiopians. Although ancient and recent ties with sub-Saharan and eastern Africans cannot be discarded, it seems that isolation, strong drift, and/or founder effects are responsible for the anomalous Y-chromosome pool of this population. These results demonstrate that, at a fine scale, the smooth, continental clines detected for several Y-chromosome markers are often disrupted by genetically divergent populations.

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